采后1-MCP和乙烯利处理对茭白呼吸代谢及细胞结构的影响

Effects of 1-Methyleyelopropene and Ethylene Treatments on the Respiratory Metabolism and Cell Structure of Postharvest Zizania latifolia

为探索茭白采后衰老的调控机制,研究了采后10μL/L 1-甲基环丙烯(1-MCP)和1.25 mg/L乙烯利(ET)处理对茭白常温(25℃)贮藏期间呼吸代谢和细胞超微结构的影响。结果显示,1-MCP处理显著抑制了茭白贮藏期间色差L、a*值、b*值和失重率的上升;呼吸强度和还原糖含量显著低于对照;超氧化物歧化酶(SOD)活性在贮藏第1 d高于对照,其余贮藏时间低于对照,琥珀酸脱氢酶(SDH)和过氧化物酶(POD)活性在整个贮藏期间低于对照而细胞色素c氧化酶(CCO)活性高于对照,维持较低的相对电导率和丙二醛(MDA)含量;贮藏6 d后细胞壁完整、线粒体清晰。乙烯利处理对呼吸和活性氧相关代谢与1-MCP处理有相反效果。以上结果表明,采后1-MCP处理可显著抑制茭白采后呼吸代谢和活性氧产生,从而有效保持能量代谢平衡和细胞结构的完整性,延缓茭白组织的衰老和品质劣变。

In order to explore the possible mechanism of postharvest senescence in Zizania latifolia, the effects of 10 μL/L 1-methyleyelopropene（1-MCP） and 1.25 mg/L ethylene（ET） treatments on the respiratory metabolism and cell structure associated with senescence in Z. latifolia stored at 25 ℃ for 6 days were investigated. The results showed that the 1-MCP treatment significantly inhibit ed the increase of L, a＊, b＊ value and weight loss of Z. latifolia, whilethe respiratory intensity and reducing sugar content were significantly lower than those in the control. The superoxide dismutase（SOD） activity in samples treated with 1-MCP was significantly induced after 1 day storage but reduced its activity during the remainder storage period. 1-MCP treatment also promoted the cytochrome c oxidase（CCO） activity, while inhibited succinatedehydrogenase（SDH） and peroxidase（POD） activities compared with the control, which resulted in a relatively low relative leakage rate and malondialdehyde（MDA） content. After 6 days storage at 25 ℃, the integrity of cell structure was still maintained. Compared with 1-MCP treatment, ET treatment had the opposite effects on respiratory and reactive oxygen species（ROS） metabolism. These results suggested that 1-MCP treatment could significantly inhibited the respiratory metabolism and ROS production, maintained the energy metabolism balance and cell structural integrity, and then retard the postharvest senescence of Z. latifolia.